The mechanism of high temperature superconductivity in the iron-based superconductors remains an outstanding issue in condensed matter physics[1]}, [2]}, [3]}. The electronic structure, in particular the Fermi surface topology, is considered to play an essential role in dictating the superconductivity[4]}, [5]}, [6]}, [7]}, [8]}, [9]}, [10]}. Recent revelation of distinct electronic structure and possible high temperature superconductivity with a transition temperature T\(_c\)  above 65 K in the single-layer FeSe films grown on the SrTiO\(_3\)  substrate provides key information on the roles of Fermi surface topology and interface in inducing or enhancing superconductivity[11]}, [12]}, [13]}, [14]}, [15]}, [16]}, [17]}, [18]}, [19]}, [20]}, [21]}, [22]}. Here we report high resolution angle-resolved photoemission measurement on the electronic structure and superconducting gap of a novel FeSe-based superconductor, (Li\(_{0.84}\) Fe\(_{0.16}\) )OHFe\(_{0.98}\) Se, with a T\(_c\)  at 41 K. We find that this single-phase bulk superconductor shows remarkably similar electronic behaviors to that of the superconducting single-layer FeSe/SrTiO\(_3\)  film in terms of Fermi surface topology, band structure and nearly isotropic superconducting gap without nodes. These observations provide significant insights in understanding high temperature superconductivity in the single-layer FeSe/SrTiO\(_3\)  film in particular, and the mechanism of superconductivity in the iron-based superconductors in general.
